CHATHAM — Visitors to Nauset Beach and two other area beaches last week observed something new in the sky, and it wasn't an aerial banner advertising beer or car insurance. It was a balloon, holding a high-tech camera designed to spot sharks.

Representatives of the Florida-based firm Altametry were on the Lower Cape last week testing equipment that they hope could be part of a future system for detecting white sharks near bathing beaches. The $10,000 trial project is being funded by the Atlantic White Shark Conservancy.

Altametry Founder and CEO John Ciampa said the trial flights at Nauset and the two other beaches were successful. The balloons held their positions in gusty breezes of more than 15 mph, and the stabilized cameras beamed high-resolution real-time images to operators on the ground. While there were no sharks to be seen at the time, the cameras were able to easily show seals, which are even smaller.

“They were underwater and we can safely say from an altitude of 200 feet with the camera we used, all the way to 8:09 p.m. when the sun had set, we were able to spot critters underwater,” Ciampa said. The video feed was also useful for lifeguards who were monitoring a swimmer who was showing signs of fatigue, and for beach administrators who wanted a quick snapshot of the number of parking spots available.

The balloons are tethered to the ground, but officials want to know whether they can also be tied to a boat or a buoy for unattended use. To that end, Ciampa said the team is hoping to work with the Coast Guard Auxiliary to test the balloon's performance when deployed from a boat, or when tethered to one of the shark-detecting buoys near Monomoy Island. Those trials are expected to take place this week, weather permitting. It appears that the balloons can be left unattended for four or five hours at a time, he said.

“We definitely could have a platform, say, a mile offshore,” Ciampa said. As long as the site could be reached by boat in 10 minutes or so in case the balloon began to lose altitude, the site would work. Should the balloon fall all the way to the water, around $7,000 worth of electronics would likely be ruined.

In one of the beach tests last week, Altametry had four balloons operating simultaneously. Ciampa said the effort proved that multiple cameras, up to 11, could be monitored by a single person. Those camera feeds could theoretically be from several different beaches, monitored in real-time by a person at another location altogether.

As a platform for aerial photography, balloons are preferable to manned aircraft and drones because they can fly lower over crowded beaches, are less expensive to operate, and are less obtrusive. In fact, beachgoers who saw the balloons last week were curious and enthusiastic.

“Unlike drones and helicopters and aircraft, the balloon was welcomed almost as a party item,” Ciampa said. “People posed with pictures of it,” and children in the water below playfully chased the shadow cast by the balloon, he said.

While the focus last week was on shark surveillance, Ciampa said the Altametry balloons are being explored for various other uses, like agriculture.

“We've been talking to cranberry people,” he said. Equipped with specialized cameras, the balloons can actually measure the water content of the berries, and how that content changes not only through the year, but through the hours of the day. The result could be more effective irrigation for healthier cranberry vines and plumper fruit.

“We've also studied beach erosion,” Ciampa said. Outfitted with a “hyper-spectral camera,” the balloons can provide high-resolution views of shifting sands and eroding cliffs from a platform that is much more stationary than an airplane or drone, he said.

Because they can be used above crowds of people, where FAA regulations prohibit the use of drones, balloons can also be an unobtrusive way to monitor large groups of people. Ciampa said he hopes to meet with Cape Cod Baseball League officials this week to discuss the possibility of using them at games.